You cannot authenticate against a network share using a device PIN or biometrics. Password credentials are required.
A device PIN can be lost if the device TPM is accidentally reset (for example, during a BIOS update). For this reason, you can't rely on it as the sole means of accessing your PC. Password sign in can be very important as a fallback, even if you don't use it everyday.
Basically, you should try not to forget your password. :-)
On some newer Windows 11 systems when people use a Microsoft account, password sign-in can be disabled altogether. This makes it impossible to access network shares or to use Remote Desktop. Password sign in would have to be re-enabled in that case. It also protects you from the scenario mentioned above.
